Is There a City of the Future?

Millionaire Mark lore has announced plans to build a utopian city in the american desert. It's expected to cost half a trillion dollars to build, and could eventually house five million people. There are other folks also looking to build cities from the ground up. And i'm wondering, when you hear a story like this, do you consider it to be a viable alternative way for us to think about the city of the future? Are you more sceptical than pie in the sky ideas this?